| 摘要 |
The invention relates to a method and an apparatus for production of tubes and the resulting product. The invention makes the production of bent tubes possible by cold drawing of a hollow tube blank (10) in one operation for reduction of the outer diameter and the wall thickness. It is characterized in that a straight tube blank is drawn through a drawing tool comprising a drawing die (13) and a straight mandrel (12) which is short relative to the tube blank and applied centrally in the tube blank. Drawing means (15, 16) attached to the tube end draw the tube along a pre-determined curved path, suitably in surface contact with a guiding device (17) with a pre-determined curved surface. For a pre-set angle between the central axis of the drawing die (13) and the central axis of the tube (10) at the exit of the drawing die, the tube gets a constant radius of curvature. Hereby production of tubes with a curvature adjusted to each purpose becomes possible. |
